attack. the columbine attack killed 13 people. and, again, in the case of columbine, you had one dominant personality who was seen as the driving force of the attacks. as dave cullen wrote at slate today, the older of the two boys, eric harris is the one who sought out the arms, collected the ammo, researched the big bombs they used, built all the pipe bombs, drew up the plans and diagrams, conducted the recon, calculated how to maximize the body count, cooked up batch after batch of failed napalm, and generally devised the plan. the other assailant at columbine, the younger one, mostly seems to have just gone along. after columbine, there was a long effort to try to figure out what might have motived that attack. there was what seems to have been a misguided focus on bullying as a possible motive for a long while. dave cullen's book on the massacre is called "columbine" mostly settled on a simpler truth that the dominant one between the two boys was clinically psychopathic.